The instant invention relates to a gripper feed device with pneumatic or hydraulic crank drives
As can be seen from studying pertinent technical literature, the trend in the fabricating industry is away from the mass product and towards greater diversification of individual product groups and simultaneous reduction of lot sizes.
It is therefore increasingly necessary to render operating and automation systems more flexible. This does not present great difficulties when the fabrication of simple parts with modest quality requirements is involved. But as quality requirements increase with respect to dimensional stability and complexity, the automation technology used becomes more comprehensive and soon reaches the limits of economic practicality. This is true above all in production fields such as chip-less shaping and in particular with punching techniques which have traditionally been highly automated. Since the possibilities for automation are relatively simple for technological reasons, thorough investigations reveal again and again that the known automation techniques have not kept pace with the development of machines. Often completely new designs are needed, as constant adaptation of existing methods must finally lead to a dead end.
It is the object of the instant invention to present such a new design for a gripper feed device with pneumatic or hydraulic crank drives for automatic forward feed of band, strip or profile material in presses, punching presses or similar machines.
This development was initiated, in addition to what has been said above, through the fact that the brochure "Differential Pressure Press--Leinhaas" (published in German in December, 1987) documents such a press which can be automated with conventional, commercially obtainable automation devices only by sacrificing its considerable technological advance. It will become clear that the mentioned new designs, and here in particular the above-mentioned forward feed, is considerably better from the point of view of its technology as well as of its cost than clumsy adaptations of existing technologies.
Only five applications and patents dealing with the abovementioned objectives have been found in the German and the European Patent Office, and these only partially touch upon the problems described.
One of these U.S. Pat. No. 2,468,236 of the year 1949, relates to a double gripper feed device which is driven directly by the press in an entirely mechanical manner.
In addition, four published documents are here described and examined with respect to their relevance.